Showing papers in "Applied Ocean Research in 1986"

TL;DR: The water wave induced seepage force on a pipeline buried in the seabed is investigated in this paper, where the pipeline is assumed to be rigid and not supported by any anchoring force.

TL;DR: In this article, a statistical analysis of slow-drift forces and motions is presented by extending an approach originally due to Kac and Siegert, and an explicit, closed-form solution may be given to the problem of determining the probability density function of the slowdrift process.

TL;DR: In this paper, a hybrid element formulation was developed to study the oscillation of linear waves with bottom friction and boundary absorption, where bottom friction is assumed proportional to flow velocity with a phase difference, while boundary absorption adopts a condition similar to the impedance condition in acoustics.

TL;DR: The Gaussian wave packet method is a versatile technique yielding precise and highly resoluted results in a short time as discussed by the authors, which can be adapted to any specific problem and can be used to test ocean structures.

TL;DR: In this paper, time invariant analog filters are presented which are appropriate for approximating ocean wave kinematics described stochastically, and the JONSWAP spectrum is used for the statistical characterization of the wave elevation.

TL;DR: In this article, the enhancement of wave forces due to interaction effects is considered for the case of two adjacent, parallel, floating bridges, and the problem is considered from a theoretical viewpoint using the linearised theory of water waves.

TL;DR: A methodology has been developed to establish second order corrections to the engineering methods and the second order Chakrabarti approximation (the ‘alternative approximation’) demonstrates good agreement with measured wave kinematics.

TL;DR: In this paper, the first four statistical moments of the response over an ensemble of program runs are investigated, leading to an assessment of the likely accuracy of these quantities as predicted by a limited number of run runs.

TL;DR: In this paper, a mathematical model for the horizontal plane slow motions of ships connected to a mooring terminal through a single elastic line is developed based on the ship manoeuvring equations and a non-linear elastic Mooring line model.

TL;DR: In this article, the wave power absorption by an oscillating water column in a reflecting wall is studied within linear theory and numerical examples demonstrate how the performance depends on the geometry of the system as well as on the frequency and direction of the incident waves.

TL;DR: In this article, the wave power absorption of a finite row of oscillating water columns in a reflecting wall is studied within linear theory, and the results for an infinite row and for a single column are compared.

TL;DR: In this paper, a method for calculating second order forces on a vertical, large diameter circular cylinder is reported, where forces at sumfrequencies and difference frequencies as well as the first order force spectrum are calculated as a result of irregular waves generated from a Pierson-Moskowitz wave spectrum.

TL;DR: Theoretical solutions for diffraction of oblique waves by an infinite vertical barrier with a small slit in deep water were obtained in this paper, where the method of matched asymptotic expansions was used to solve two problems: (1) thin barrier where the thickness of the barrier is small in comparison with wavelength, and (2) wide barrier where both the wavelength and the thickness are in the same order of magnitude.

TL;DR: In this paper, the hydrodynamic force per unit length of a circular cylinder moving in a plane perpendicular to its axis in a nonuniform unsteady flow of an ideal fluid of infinite extent is formulated as a series expansion in the small parameter ka, where a is the cylinder radius and k−1 the length scale of the flow.

TL;DR: In this article, the effect of a uniform current on slowly varying forces is examined in a two-dimensional model where the body is either a restrained or a moored submerged circular or elliptic cylinder.

TL;DR: In this article, methods for the calculation of scattering and dissipation of surface waves by a bi-plate structure are provided and compared with wave-flume experiments, and theoretical results are in good agreement with the measurements.

TL;DR: In this article, a simple single degree of freedom model of an offshore structure is used to study the effects of thenonlinear hydrodynamic drag force on the structural response to oscillatory flow with or without a steady component.

TL;DR: In this paper, an equivalent box technique is developed to derive an analytical solution for the approximate predictions of the irregular frequencies associated with a source or a mixed source-dipole distribution method analysis of an arbitrarily-shaped three-dimensional (3D) marine structure which is free surface piercing.

TL;DR: In this paper, a linear long wave mathematical model is formulated and processed to a compact one equation form, for the description of the generation and propogation of seismic origin water waves.

TL;DR: In this paper, the problem of minimizing the maximum bending moment in an offshore pipeline is formulated by finding suitable values of horizontal tension and suspended length such that the maximum moment in the pipeline is as low as possible, without violating constraints on the lift off angle and geometric constraints.

TL;DR: In this article, a suitable design for general marine use is described, taking account of fitting, materials and marine growth, and model tests on an isolated cylinder demonstrate the effectiveness of the geometric configuration, when one cylinder is directly downstream of another, spoilers are less effective in reducing response.

TL;DR: In this paper, a suitable design for general marine use is described, taking account of fitting, materials and marine growth, and model tests on an isolated cylinder demonstrate the effectiveness of the geometric configuration, when one cylinder is directly downstream of another, spoilers are less effective in reducing response.

TL;DR: In this paper, the response of a simplified offshore structure to waves is examined, the structure being idealized as a mass mounted on a light circular cantilever cylinder of uniform cross-section.

TL;DR: In this article, the authors decrit ce modele base sur l'equation bien connue de Paris specifiquement applicable a des structures offshore tubulaires, and decrit l'analyse des donnees obtenues dans la litterature publiee and par d'autres sources.

TL;DR: Experimental and numerical stress analysis have been conducted on a novel joint known as an extruded joint as discussed by the authors, which has been found that significant benefits could be obtained, in terms of fatigue strength, for extruded joints in comparison with conventional welded joints.

TL;DR: In this article, the quasi-one-dimensional gravity current formulation of Ellison and Turner is modified to accommodate a streamwise variation of bottom slope and gravity current width, and a simplified width evolution model is hypothesized, namely, each lateral boundary of the steady current penetrates the ambient fluid as if it were (locally) the head of a temporally evolving gravity current along a horizontal bottom.